A sealing ring, comprising at least one dynamically stressed lip seal and a preliminary seal, which is disposed at an axial spacing in an adjacent manner to the lip seal, wherein the preliminary seal is composed of an electrically conductive material, is generally known, as is a seal arrangement, which comprises such a sealing ring. The sealing ring in this case may be configured as a radial shaft sealing ring, wherein the lip seal faces the medium to be sealed in an axial direction. In contrast, the preliminary seal faces the environment in an axial direction.
The preliminary seal is tasked with inhibiting contaminants from the environment from penetrating to the lip seal. This results in better functional properties of the lip seal over a longer operating life.
A sealing ring and a seal arrangement formed therewith are known from DE 103 40 802 A1. The sealing ring comprises a first component, which displays at least one lip seal, wherein this component of the sealing ring is composed of an electrically conductive material having rubber-elastic properties. The previously known sealing ring is used for sealing components, which include toothed parts, wherein charge separations occur during movement of these toothed parts. The resulting flows are thus in part diverted by a lubricant used, and in part the flows are conveyed further to the components to be sealed in relation to one another. As a result of the electrically conductive and rubber-elastic material, of which the first component of the sealing ring is composed, it is advantageous that flows may be simply diverted through the sealing ring. In one of the previously known exemplary embodiments, a dirt lip is associated with the dynamically stressed lip seal on the side facing axially away from the space to be sealed, which is formed integrally with, and of the same material as, the lip seal, and is thus also composed of an electrically conductive and rubber-elastic material. Polyamide is cited as an example of an electrically conductive material.
Another sealing ring is known from DE 103 14 924 A1, which is used in a seal arrangement for sealing a machine element, preferably a shaft. The sealing ring comprises a depot for absorbing leakage, wherein the depot is monitored by a measuring device. The measuring device is formed by a capacitor, and the depot functions as a dielectric. The depot is preferably configured as an absorbent or swellable, substantially annular disc which is composed of a porous material. The depot may be composed of a non-woven material, which changes its dielectric properties only by absorbing the leakage. The change in the measurable capacity of the depot associated therewith constitutes in this case the measure of the saturation of the depot by leakage. By measuring the capacity, it is possible to draw conclusions about the amount of leakage of the fluid in the depot.